1. Field of the Invention
The present invention relates to a fire extinguishing head for use in large exhibition halls, atriums, gymnasiums or the like. More particularly, the present invention relates to a fire extinguishing head capable of sprinkling water evenly on a large rectangular fire area, for example, a fire area of 5 m wide.times.20 m long.
2. Description of the Related Art
Hitherto, to evenly sprinkle water on a wide rectangular fire area, a fire extinguishing head comprising a plurality of nozzles which have different shooting ranges from each other and are arranged in the upper and lower portions thereof has been used. The nozzles are disposed in the fire extinguishing head in sequence from the top: a long range nozzle, a medium range nozzle having a range shorter than that of the long range nozzle, and a short range nozzle having a range shorter than that of the medium range nozzle.
The conventional fire extinguishing head, however, has the problems described below.
1) Discharge water flow discharged from the short range nozzle draws air together with discharge water flow discharged from the medium range nozzle, and discharge water flow discharged from the medium range nozzle draws air together with discharge water flow discharged from the long range nozzle. For this reason, the shooting range of each nozzle decreases less than a designed value, and therefore it is not possible to sprinkle water evenly all over a wide rectangular sprinkling area of a length as great as 20 m; PA1 2) Since the sprinkling area of each nozzle is predetermined, for example, the long distance area for the long range nozzle, or the medium distance area for the medium range nozzle, the particle diameter of discharge water differs in different areas. PA1 3) Since the sprinkling area of each nozzle is predetermined, it is difficult to evenly sprinkle water in a neat rectangular discharge water pattern.